M35 Pill – Uses, Dosage, Side Effects, Interactions

What is the M35 Pill?


The pill with imprint M 35 is yellow and contains chlorthalidone 25 mg, a medication that belongs to a class of drugs called antihypertensives/diuretics.

Its brand name is Thalitone. It was originally approved by the US Food and Drug Administration in 1960. Currently, it is produced by Mylan Pharmaceuticals Inc.


It is typically used to treat edema, an abnormal accumulation of fluid in the interstitium, located in the cavities of the body. It may be caused by conditions like liver, heart, or kidney disease.

Moreover, the medication is used alone or in combination with other drugs to treat high blood pressure. This is very useful since hypertension adds to the workload of the arteries and heart. If it continues for a long time, they may not function properly and can damage the blood vessels of the heart, brain, and kidneys, ultimately leading to heart failure, stroke (also known as a cerebrovascular accident), or kidney failure.

Note – unlike loop diuretics (they act at the ascending limb of the loop of Henle – a portion of a nephron – in the kidney), the efficacy of chlorthalidone is substantially diminished in sufferers with chronic kidney disease.


It comes as a tablet to take by mouth and is commonly taken once per day or every other day after a meal. Its bioavailability is about 64 percent.

The usual recommended dosage for heart failure is 12.5 to 100 mg per day. The usual recommended dosage for edema is 100 mg every other day or 50 to 100 mg per day. The usual recommended dose for hypertension is 25 to 100 mg a day.

The maximum recommended dose is 200 mg per day.

Notes – because chlorthalidone may cause you to pass urine more often, try to take it before 6 pm. Consult your healthcare provider if you have questions about your dosing schedule. You should also maintain a strict exercise and diet regimen along with this treatment to get the best possible effect.

Side Effects of M35 Pill

Common side effects may include:

  • constipation;
  • diarrhea;
  • headaches;
  • loss of appetite;
  • muscle spasm;
  • dizziness.

Rare side effects may include:

  • fast or uneven heartbeat;
  • vomiting;
  • muscle weakness or pain;
  • nausea;
  • red or purple spots on the skin;
  • unusual thirst;
  • numbness or tingly feeling;
  • dry mouth;
  • yellowing of the skin or eyes;
  • unusual weakness;
  • low fever;
  • clay-colored stools;
  • dark urine;
  • loss of appetite;
  • easy bruising or bleeding;
  • feeling weak or light-headed.

The presence of other medical conditions may negatively affect the use of this chlorthalidone. Therefore, make sure you tell your healthcare provider if you have any other medical problems, particularly:

  • gout (a form of inflammatory arthritis which occurs in some people who have high levels of uric acid in the blood);
  • hypercalcemia (high calcium in the blood);
  • anuria (not able to form urine);
  • hypochloremia (low chloride in the blood);
  • asthma;
  • hyponatremia (low sodium in the blood);
  • type 2 diabetes mellitus;
  • kidney disease;
  • hyperuricemia (high uric acid in the blood);
  • liver disease;
  • systemic lupus erythematosus;
  • low phosphorus in the blood (hypophosphatemia);
  • low magnesium in the blood (hypomagnesemia);
  • low potassium in the blood (hypokalemia).

Pregnancy & Breastfeeding

This diuretic is not recommended for use in pregnant women unless absolutely necessary. In addition, you should avoid it if you are breast-feeding a baby.

Drug Interactions

It may negatively interact with other medications, especially:

  • diabetes medications;
  • nonsteroidal anti-inflammatory drugs, such as – naproxen (Naprosyn), ibuprofen (Motrin or Advil), and nabumetone (Relafen);
  • tramadol;
  • drugs containing lithium;
  • venlafaxine;
  • digoxin (Lanoxin);
  • loop diuretics, such as – bumetanide (Bumex), furosemide (Lasix), and torsemide (Demadex).


Avoid drinking alcoholic beverages while taking this diuretic since it can increase some of the side effects, like – fainting, dizziness, and a very low blood pressure.


In case of overdose, call your local poison control center at 1-800-222-1222.

Image credit – Shutterstock

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